The present invention comprises a new and distinct cultivar of Rhododendron hybrid known by the varietal name ‘Microhirs3’. The new variety was discovered in 1997 in Ahrensburg, Germany. The new variety is the result of a planned breeding program, with the intended purpose of providing lime tolerant rootstock varieties, between an unnamed and unpatented Rhododendron hirsutum variety (female parent) and an unnamed and unpatented Rhododendron micranthum variety (unpatented male parent). ‘Microhirs3’ exhibits similar corolla form and size to its female parent, but differs from its female parent in flower color and amount. Additionally, ‘Microhirs3’ exhibits a similar number of flowers per inflorescence to its male parent, but differs from its male parent in corolla color and form. When compared to Rhododendron variety ‘Intermedium’ (unpatented), the new variety is similar in corolla and leaf form, but differs in the color of and amount of flowers. ‘Microhirs3’ has been trial and field tested and has been found to retain its distinctive characteristics and remain true to type through successive propagations.